FreeBSD unstable on Dell 1750 using SMP?

Dan Charrois dan at
Tue Nov 29 22:24:06 GMT 2005

Rutger Bevaart wrote:
> Same here on several 1750's, 1850's and 2850's. Tomorrow I'll  
> disable USB
> in the BIOS on one of the 1750's and see if it makes a difference.  
> It's
> the only one of the set that I could get downtime for because it  
> rebooted
> yesterday ;-)

I've disabled USB in the BIOS on my 2850 much earlier on when I was  
getting interrupt storms, since I didn't need USB anyway.  It solved  
the problem of the interrupt storms, but it didn't seem to have any  
impact on the mysterious unsolicited rebooting problem.

Claus Guttesen wrote:
> It's not any comfort to you but I have two Dell PE 1750's running very
> reliable using FreeBSD 5.4 stable as of Wed. the 28'th of Sep. 2005.
> It has two Xeon at 3 GHz, 2 GB RAM, a LSILogic 1030 Ultra4 Adapter.
> HTT is *off*.
> HTT does not yield any higher performance for most purposes. I can
> send you my kernel if you want.

It actually may be a comfort, since perhaps HTT is related to the  
culprit.  Since the last crash, about a month ago, I disabled HTT,  
both in the kernel as well in the BIOS.  So as far as I know, it's  
completely been disabled (and the boot messages and top only show 2  
CPUs).  And I haven't had the system go down for nearly a month now.

Of course, I also did some other things at the same time, so it's  
unclear as to which specifically may have helped.  I had noticed that  
in the past it had rebooted itself twice right while running  
mysqlhotcopy as root during a period where the server may have been  
rather heavily loaded.  So in addition to turning off hyperthreading,  
I also changed the time when mysqlhotcopy was running to a period  
likely under a lighter load, and modified things so it isn't running  
as root any longer.

Not that I think mysqlhotcopy was the culprit itself, but it does  
cause a fairly large burst of disk activity when it is running, and  
it does seem to be related to triggering the event, at least in my  

In any case, since I've done those three things, I haven't had a  
crash yet.  Of course, the lack of a result doesn't prove anything,  
but the more time that passes, the better I feel.  That is until one  
day I wake up to find that it died again.  In any case, if that  
happens, I'll know more things that the problem isn't related to..

Vivek Khera wrote:
> I'd recommend running the Dell diags.  They're pretty good at picking
> out hardware trouble, which it sounds like the OP is having.

In my case anyway, I have run the Dell diagnostics, and they showed  
everything to be just fine..

Kevin Oberman wrote:
> As far as I can tell, hyperthreading is not much of a win for  
> anyone. See hte
> article at: 
> 0,39020330,39237341,00.htmhttp://news.zdnet
> It reports that HTT slows performance even on threaded and,  
> theoretically HTT
> ideal apps. (And this was with Windows.)

So I've heard.  I was hoping that hyperthreading might be able to  
help a dedicated MySQL server handle a bit higher load, but I never  
had the chance to benchmark it with and with hyperthreading before I  
had to put the machine into production.  So it's disabled now - it  
can't hurt the stability of the system and can only potentially help  
it.  Time will tell.

Thanks for your replies, everyone!

Syzygy Research & Technology
Box 83, Legal, AB  T0G 1L0 Canada
Phone: 780-961-2213

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